THE VORTEX: From Soap Bubble to Jupiter’s Great Red Spot
A report in Nature Scientific Reports 3, Article number: 3455: “Intensity of vortices: from soap bubbles to hurricanes” by T. Meuel et al.
Open Access || Published 13 December 2013
Vortices are prominent features of fluid flows and span length scales ranging from an insect’s length to planetary sizes. Understanding the displacement of vortices, their structure, and their long time dynamics is crucial for different aspects be they at the level of small engines, turbulent flows, or planetary atmospheres.
Vortices may be found in turbulent flows, where they appear at all scales, in the wake of a bluff body, where they come in pairs, or in atmospheric flows whether on earth or on other planets …
Here we use a half bubble heated from below on which large isolated vortices are observed. … Read more …
(a) The Set Up: a brass disk (1) with a circular groove (3) can be rotated using a continuous motor (6) connected to it by a shaft (5). This disk is heated by the proximity of a hollow annulus (2) connected to a water circulation bath. The bubble is blown using the soap solution in the groove (3). The inner side of the brass disk is covered by a Teflon coating (2 mm thick) to minimize the heating of the air inside the bubble. The temperature at the equator of the bubble is set by the temperature of the water bath.
(b) and (c) show the detachment of thermal plumes from near the equator and rising towards the pole; they were taken using (b) an infrared camera (the temperature scale is in deg °C) and(c) a CCD color camera .
(d) The full bubble with a vortex being formed by a large thermal plume.
(e) A zoom on the vortex in which the colors are interference colors of white light being reflected by the thin water layer constituting the bubble.
(f) Numerical simulation of thermal convection on the surface of a sphere of radius 1, where the colors indicate the vorticity field.
(g) A zoom on the single vortex in image (f). The color code indicates the value of the vorticity …